BOSCH GMS120-27 Wall Scanner
- Wood, metal, copper and live AC wire detection
- Center indication with material identification
- 2 AA batteries included, or Bosch 3.7V Li-Ion pack
- IP54 rated, shock-absorbing rubber casing
- One-year limited warranty, plus a year on registration
Last refreshed Sep 7, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A multi-material wall scanner that finds stud centers, metal, copper pipe and live wiring, with a clear marking ring for transferring hits. Detection depth is not stated, so check it before relying on it in thick walls.
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ASIN: B0DBWSSPT2Model: GMS120-27Category: Stud Finders
Overview
Electricians, plumbers and remodelers get one scanner that reads wood studs, metal framing, copper pipe and live AC wiring behind drywall. You glide it across the wall, the display shows the object center and material type, and a lit ring turns green or red to flag a live wire.
Knowing what is behind the drywall before you drill, not just where a stud edge is, makes it useful for trades and careful DIY work alike. Power flexibility helps too, since it runs on AA cells out of the box or a Bosch rechargeable pack. The listing never states scan depth, a figure many pros want before trusting a reading.
Who it's for
Trade workers and homeowners drilling into interior drywall for mounts, anchors or new runs get material identification plus a live wire warning. Someone needing a stated depth range should confirm specs with Bosch first.
Pros and cons
- Identifies wood, metal, copper and live wire
- Shows stud center, not just edges
- Color ring flags live wiring
- Runs on AA or Bosch Li-Ion pack
- Detection depth not listed
- Li-Ion battery sold separately
- Drywall is the only wall type named
Performance notes
Accuracy depends on gliding the tool steadily across the wall so the sensor can map the object and its center. Material identification separates wood, metal and live AC wire, and the illuminated ring helps transfer the reading to a pencil mark. The listing describes performance behind drywall only.
Specifications
| Brand | Bosch |
|---|---|
| Model | GMS120-27 |
| Dimensions & fit | |
| Item Weight | 0.86 pounds |
| Item Dimensions | 7.3 × 3.4 × 1.3 inches |
| Construction & materials | |
| Material Type | Plastic |
| Included components | |
| Unit Count | 1 |
| Included Components | (1) GMS120-27 Wall Scanner, (2) AA Batteries, (1) Soft Pouch |
| Warranty & support | |
| Warranty Description | Bosch measuring and layout tools are covered by a one year limited warranty with an additional year when you register your tool within eight weeks of purchase - for details,call 1-877-BOSCH99 |
| Other details | |
| Number Of Items | 1 |
| Part Number | GMS120-27 |
| Item Type Name | Detection Tools |
| Style Name | Industrial |
| Item Highlight | Multi function wall detector scanner with center indication, metal stud finder for electricians, plumbers & contractors |
| Measurement Accuracy | 0.06 |
Frequently asked questions
Can the Bosch GMS120-27 help place wall mounts and anchors?
Yes. Bosch says it is meant for marking stud centers before adding wall mounts, screws and anchors to interior walls, and it reads through drywall.
How does the Bosch GMS120-27 warn about live wires?
The color-coded marking ring turns green for safe and red when a live wire is detected, alongside the graphical display.